Cognitive Psychology and its Applications
Human information processing
Cognitive Psychology uncover the laws of information
processing and behavior through experiments. It
focuses on the complex, cognitive thinking and
knowledge-related aspects of system performance,
whether carried out by human or by machine agents.
It asks fundamental questions and required no further
application.
Human Factor is a study toward system design,
accounting for those factors, psychological and
physical, that are properties of the human
component. Applied to knowledge by designing systems that work for humans (intergrating
human in the system) and accommodate the limits of human performance. It is directly
applied the problems. Places a greater emphasis on developing usable design principles.
Focuses on information processing capacities of the brain.
Engineering psychology is a discipline within psychology, whereas the study of human
factors is a discipline within engineering. The ultimate goal is to understand the human mind
as is relevant to the design of systems. Engineering psychology places greater emphasis on
discovering generalizable psychological principles and theory. Psychological perspectives to
the problems of system design.
Basic research Applied research
, Theory, basic principes Particular population, task, product, system,
environment
Generalizable Face value
Controlled
But: artificial, not specific But: narrow scope (only for that task),
Has to be finetuned to be useful expensive, possible confounds, ethical
aspects
Human factors is the study of interaction between humans and systems in rder to improve
performance, safety, health and usability. Related disciplines are ergonomics and AI.
Ergonomics is more focused on physical aspects.
AI works more with expert systems and machine learning instead of people.
Goals of human factors are:
Development of generic knowledge (engineering psychology)
Enhance efficiency (productivity)
Ensure safety, reduce error
Assure tasks are within human capability
Increase user satisfaction, comfort
Improve human performance
Gain market acceptance
Reduce costs (economic, legal, social)
Development of tools and equipment
Design and evaluation cycle
Six major stages of human factors
in the product life cycle include: (1) fro
nt end analysis, (2) iterative design and
test (3) system production, (4) implementat
ion and evaluation, (5) system oper-
ation and maintenance, (6) system disposal.
User-centered design meanings are ‘know the
user’ and ‘honor the user’. This means the human
factors specialist will study the users’ job or task
performance, elicit their needs and performance,
ask for their insights and design ideas, and
request their response to design solutions. User-
centered design does not mean that the user
designs the product or has control of the design
process. The goal of the human factors specialist
is to find a system design that supports the user’s
need rather than marking a system to which users must adapt. User-centered design is also
embodied in a subfield known as usability engineering:
Early focus on the user and tasks
Empirical measurement using questionnaires, usability studies and usage studies
focusing on quantitative performance data
, Interactive design using prototypes, where rapid changes are made to the interface
design
Participatory design where users are directly involved as part of the design team
Problem solving is the most common way in the human factors cycle. It is cheap and a quick
‘fix’. At the end is this the most expensive way.
The cost of human factors design
Can be relatively low More expensive
Consultancy User centered design
Expert review Complete task analysis
Tests Surveys
Experimental research
The practice of good human factors is just as relevant to designing systems that are effective
at the start and thereby anticipating and avoiding the
human factors deficiencies before they are inflicted on
system design. The role of human factors in the design
loop can just as easily enter at point B as at point A. If
consideration for good human is given early in the
design process, considerable savings in both money
and possible human suffering can be achieved.
Benefits of Human Factors are:
Prevention of accidents
Prevent compensation payments
Less support for customers
Less sick leave, higher job satisfaction
Higher productivity, more efficiency
Lower costs for training and instruction
Iterative design is using prototypes
Usability testing
Designers conduct heuristic evaluations and other studies to narrow the possible design
solutions for the products/system. They can determine whether it will cause excessive
physical or psychological loads, and they analyze associated hazards. If the system involves
controls and displays with which the user must interact, there is one task left. The system
must be evaluated with respect to usability. Usability is primarily the degree to which the
system is easy to use or ‘user friendly’. This including the following five variables:
Learnablitiy: The system should be easy to learn so that he user can rapidly start
getting some work done
Efficiency: The system should be efficient to use so that once the user had learned
the system, a high level of productivity is possible.
Memorablility: The system should be easy to remember so that the casual user is
able to return to the system after some period of not having used it, without having
to learn everything all over again
, Errors: The system should have a low error rate so that users make few errors during
the use of the system and so that if they do make errors, they can easily recover from
them. Further, catastrophic errors must not occur.
Satisfaction: The system should be pleasant to use so that users are subjectively
satisfied when using is; they like it
Usability is only a small part of what HF has to offer!!
Front end analyses
User analysis
o Who are the users
Environment analysis
Determine goals, function, tasks
o Goal: highest level (e.g. for mobile phone: communication)
o Functions: functionalities (e.g. making a call, sending an sms)
o Tasks: actions of the user(s) (e.g. selection number, making a call)
Goal important because it may be reached with a completely different system
Task analysis
Physical Cognitive
Use of tools, instruments Decision making, problem solving is complex
Large amounts of knowledge are needed
There are complex rule structures
Collecting data:
Observations
Think aloud
Interviews
Surveys
Experiments
Research methods
Literature study
Experimental research (controlled)
An experiment involves looking at the relationship between causal independent
variables and resulting changes in one or more dependent variables, which are
typically measures of performance, workload, preference, or other subjective
evaluations. The goal is to show that the independent variable, and no other variable,
is responsible for causing any quantitative differences that we measure in the
dependent variable.
o Lab study
o Field study
Problem with experimental research:
Subjects are not representative
Confounding variables
Power too low
Descriptive research (less/not controlled)